XJ gots no go

chris

chris

cltdba
Moderator
Joined
Sep 28, 2009
Location
Concord, NC
I've started having a peculiar problem with my XJ and was hoping you guys could help me troubleshoot. The problem started last weekend at Mountain City, but has gotten much worse.

When I step hard on the gas, to the floor, I can hear the intake gulping in the air and the engine revs but it just has no power at all. In 2WD it slows almost to a crawl while going up the small hills on the state roads at URE. In 4-lo I can barely spin the tires when trying to climb up the rocks.

Here's what I've done recently. Replaced fuel filter prior to the problem to help shorten the starting times. Takes at least 5 seconds to start. Had all of the frame plating and armor put on in addition to long arms. Wired up 8 fog lights using relays. 3 relays, 3 switches all on their own circuit. Running them off of 8 gauge wire straight from battery. (It was running an amp before.) All of this work was done prior to going to Mountain City.

FYI, I am now also seeing oil blow by into the air box that wasn't there before.

My first guess is crank position sensor. The plug wires, cap and rotor all look new. Haven't pulled the plugs, but it idles just fine and it revs good as well. Seems to only happen when there is a load on the engine.

Any suggestions?
 
Transmission slipping? If the engine is revving but the truck is not moving/accelerating then it could be a transmission issue.

5 speed or auto? If auto, check your transmission fluid level and see how the fluid looks and if it smells burnt.
 
reminds me of my Throttle Position Sensor failure - are you throwing a CEL?

By the way...what killed my TPS is unknown...but it happened after I pressure washed the engine.....maybe it was just it's time. It ran fine, but would stutter/lose power as I would put a load on the motor.

I'd wait for some other ideas before you go run/buy a TPS - ohh yeah...AutoZone will pull the codes from your car for FREE if you don't have a reader.

EDIT: Just saw your XJ is pre OBD-II.....now your analysis changes - Good Luck
 
Cat still present?
 
Transmission is good, not slipping at all. Putting it in 4LO allows it to achieve forward momentum.

Cat is still present. I experienced something similar to this once when I thought my muffler collapsed. I cut it off and replaced with a cylinder style muffler. Problem solved. Perhaps it was my cat back then and I just happened to rattle the guts loose when I sawzalled the pipe and the muffler change was just a coincidence? It's the original cat as well. I was thinking along the exhaust route earlier today and put my hand at the pipe. It was extremely hot coming out. Could very well be a backup in the cat. There's no way I can unbolt the thing. Too rusted. I'd have to cut it off and weld in a new one. Might be time to go that route.

Anything else that might cause this?
 
x3 on the cat
 
I'm gonna try the cat first because it seems like the most likely cause with the symptoms I'm having. Now to find a good inexpensive hi-flow cat.
 
I want to keep it street legal. Plus the bolts are shot and it's not coming off without cutting. Might as well replace it.
 
Magnaflow from ebay. Usually, you can pick one up for under $80. You could probably get one from a local exhaust shop for about the same price. I got mine from a local shop for about $85, I think.
 
Magnaflow offers two types of converts, direct fit and universal. Should I go with the bolt on direct fit or get the universal and trash the bolts that ALWAYS rust and seize up?
 
trash the bolts, and also start it and let it idle for a while, had the same prob. w/ my xj, and when it ran for a while the pipe prior to the cat whole start getting cherry red, you could also check it w/ a infrared temp. gauge, if you dont have one i could swing by w/ mine or you can come and borrow it if you want., call me if you need it 704-706-4601 darrell:beer::beer:
 
Do as GotWood said. Gut the cat and reinstall the housing. State inspection on your XJ is visual only for the emissions components. Also free up some power for next to nothing. My old XJ ran great with just a CherryBomb. BTW the cats on my DD Chevy are done like this.
 
You may also want to check your fuel pressure. Pump could be going or reg could be bad or going bad.
 
Got the cat changed out today and voila! Problem solved. Fantastic! Now I gotta get those brakes fixed. Can't seem to find any WJs in the yards around town.. :(

Thanks for the help guys!
 
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